The field of the invention relates generally to controlling aircraft in flight, and more specifically, to a flight management system for use with an aircraft and method of operating an aircraft in a controlled airspace.
At least some known aircraft include flight management systems and for generating a flight path from a departure airport to a destination airport and for flying the aircraft along the generated flight path. In today's airspace, delays due to congestion are common. When the number of aircraft entering an airspace exceeds the number of aircraft that can be safely handled by the available Air Traffic resources (limited by the number of controllers and type of automation), delays are imposed on aircraft. These delays are typically achieved by instructing aircraft to reduce speed, using radar vectors, or by orbital holding. Currently, air traffic controllers estimate, based on experience, using an average flight time to determine when to ask an aircraft to leave its current holding pattern in order to meet a time (for metering or merging with other aircraft in a defined arrival sequence) at a point after leaving the hold, such as within the arrival procedure.
At least some known aircraft include an autoflight system that includes a flight management system and a separate autopilot system. Currently, a pilot or navigator receives instructions from the air traffic controller when a delaying maneuver is required and manually enters tactical commands into the autopilot system. The autopilot system abandons the flight path generated by the flight management system, and operates the aircraft through the delay maneuver based on the tactical commands. Because the generated flight path has been abandoned, the intent, or future position of the aircraft becomes uncertain. As a result, the flight time will vary significantly based on where the aircraft leaves a delay maneuver, introducing uncertainty which requires additional separation buffers. This uncertainty results in decreased capacity and increased fuel burn for following aircraft due to their increased time spent in the delaying tactical operation.
In addition, at least some known air traffic controllers may use trajectory based operation methods to maintain aircraft separation. This method requires knowledge of the future aircraft 4-dimensional intent (latitude, longitude, altitude and time). Known autoflight systems do not support trajectory based operation methods because the autopilot system abandons the generated flight path to execute tactical commands received by the air traffic controller.
An integrated autoflight system is needed that eliminates the undesired uncertainty of an aircraft's intent during implementation of tactical commands. Specifically, an autoflight system is needed that generates a flight path that is indicative of the future aircraft trajectory based on tactical commands, and downlinks the flight path trajectory to the ground controllers to provide the ground controllers with a precise picture of the aircraft's position in time and enable controllers to safely merge aircraft traffic with appropriate separation for approach and landing on an active runway.